Vehicular audio-amplifier controller

Abstract

A vehicular audio-amplifier controller includes: a delay buffer that stores a sound signal supplied from a signal source; a first processing unit that applies an absolute value process to the supplied sound signal; a second processing unit that applies a low-pass filter process and an offset process to a processing result of the first processing unit; a power supply controller that performs control to change a voltage value of a vehicular power supply according to at least a signal value processed by the second processing unit and a type of the signal source; and a sound signal output unit that outputs a sound signal stored in the delay buffer with only a delay time that is determined based on a power supply control process time of the power supply controller.

The invention claimed is: 
     
       1. A vehicular audio-amplifier controller comprising:
 a delay buffer that stores a sound signal supplied from a signal source; 
 a first processing unit that applies an absolute value process to the supplied sound signal; 
 a second processing unit that applies a low-pass filter process and an offset process to a processing result of the first processing unit; 
 a power supply controller that performs control to change a voltage value of a vehicular power supply at least in accordance with a signal value processed by the second processing unit and a type of the signal source; and 
 a sound signal output unit that outputs the sound signal stored in the delay buffer with only a delay time that is determined based on a power supply control process time of the power supply controller; wherein 
 the delay time is set appropriately according to the signal source. 
 
     
     
       2. A vehicular audio-amplifier controller comprising:
 a delay buffer that stores a sound signal supplied from a signal source; 
 a first processing unit that applies an absolute value process to the supplied sound signal; 
 a second processing unit that applies a low-pass filter process and an offset process to a processing result of the first processing unit; 
 a power supply controller that performs control to change a voltage value of a vehicular power supply at least in accordance with a signal value processed by the second processing unit and a type of the signal source; and 
 a sound signal output unit that outputs the sound signal stored in the delay buffer with only a delay time that is determined based on a power supply control process time of the power supply controller; wherein 
 the power supply controller starts power supply control at a time point that is just a predetermined power supply transition time before a time point of outputting a sound signal from the sound signal output unit following a change in type of the signal source, and 
 the predetermined power supply transition time is shorter than the delay time. 
 
     
     
       3. A vehicular audio-amplifier controller comprising:
 a delay buffer that stores a sound signal supplied from a signal source; 
 a first processing unit that applies an absolute value process to the supplied sound signal; 
 a second processing unit that applies a low-pass filter process and an offset process to a processing result of the first processing unit; 
 a power supply controller that performs control to change a voltage value of a vehicular power supply at least in accordance with a signal value processed by the second processing unit and a type of the signal source; 
 a sound signal output unit that outputs the sound signal stored in the delay buffer with only a delay time that is determined based on a power supply control process time of the power supply controller; and 
 a correction unit, wherein 
 when a processing result of the second processing unit is smaller than a processing result of the first processing unit, the correction unit corrects, within the delay time, the processing result of the second processing unit so as to be larger than or equal to the processing result of the first processing unit. 
 
     
     
       4. A vehicular audio-amplifier controller comprising:
 a delay buffer that stores a sound signal supplied from a signal source; 
 a first processing unit that applies an absolute value process to the supplied sound signal; 
 a second processing unit that applies a low-pass filter process and an offset process to a processing result of the first processing unit; 
 a power supply controller that performs control to change a voltage value of a vehicular power supply at least in accordance with a signal value processed by the second processing unit and a type of the signal source; and 
 a sound signal output unit that outputs the sound signal stored in the delay buffer with only a delay time that is determined based on a power supply control process time of the power supply controller; wherein 
 when a power supply transition time for power supply control performed by the power supply controller is greater than or equal to the delay time, the power supply controller performs the power supply control based on a maximum output from the signal source. 
 
     
     
       5. The vehicular audio-amplifier controller according to  claim 1 , wherein the delay time is set appropriately according to a type of the signal source.